At present, time slots are frequently employed to condition the possibility of opening a protected enclosure in order to avoid as far as possible criminal violation of the protection and exposure to serious risks of the operating personnel.
Thus, blocking means have already been associated with locks which prevent operation during certain periods of the day, even for people who either possess the key to the lock or possess the code for the opening thereof if controlled in a more complex manner. If in this manner the periods of removal of the ban are reduced to a minimum, the risks of violation are evidently less.
The main problem which such an installation poses is that of determining the time slots corresponding to the removal of the ban which is arranged preferably in an automatic manner so that the personnel who must daily serve the protected enclosure are unable to modify the data relating to the slots, at least in the sense of enlarging the latter. This impossibility for the personnel to open the protected enclosure constitutes for them additional security since an attack, occurring outside the time slots when the ban is removed, may thus be thwarted by the impossibility inherent in the system of being able to be opened. Even the order to open the protected enclosure under the threat of arms cannot lead to the opening thereof since the personnel having available the key or the code for the opening is unable to bring about such opening.
It is furthermore desirable that the time slots may be modified as a function of circumstances such as the changing of the opening hours of the teller cages of a bank, the inauguration of night sales in a department store or, for another establishment, the period of closing by reason of holidays for example. Such an adaptation must naturally be realized by authorized persons who may or may not be those belonging to the personnel habitually employing the protected enclosure.
It is to this problem of creating a system of the type hereinabove indicated that the invention advances a solution in providing an easily adaptable arrangement for the removal of a ban of convenient operation and of great flexibility as to its possibilities of installation on protected enclosures of every type.